1. Field of the Invention
This invention relates to a single-piece stamped and formed electrical receptacle terminal.
2. Description of the Prior Art
In many applications in the electrical industry it is a continuous requirement to provide more cost-effective yet more compact, sturdy and reliable electrical terminals. It is common to find electrical terminals stamped and formed from sheet metal that have a connection section such as a crimp barrel for connection to a conducting wire, further comprising a contact section for connection to a complementary terminal, and means for securing the terminal within the cavity of a connector housing. It is common to find receptacle terminals for mating with tab or pin terminals to have resilient cantilever beam contact arms extending from opposed sides of the terminal to receive the complementary pin or tab therebetween. In certain applications, an additional outer spring body stamped and formed from a stronger material such as stainless steel is positioned around the contact section of the terminal and serves to provide means for securing the terminal within the connector housing and extra spring support for increasing the spring strength of the inner contact arms. Such an outer spring body often has the effect of protecting the inner contact area thus making the receptacle terminal more robust, but also increases the contact pressure and provides a stronger support for securing of the terminal in a connector housing.
A two part terminal is however costly to produce, in comparison to a one-piece terminal, for example as shown in U.S. Pat. No. 4,148,547. The latter terminal does not however have an outer cage that is robust because side and tops walls are separate from each other. Furthermore the outer cage side walls require a long strip of sheet metal leading to a lot of material waste. A single piece terminal with a more robust outer cage is shown in European patent EP 125927B where cantilever beam contact arms are folded into the cage from the top wall seam. Here also, there is high material wastage because the width of the layout of the crimping barrel is much less than the cage and contact arm section.
A terminal according to French patent application 2 751 793 overcomes certain of the aforementioned problems by reducing material usage and providing a well protected inner receptacle contact section in a single piece design. The cantilever beam contact arms are protected from the effects of false insertion of a mating pin terminal by provision of a front wall that guides and locates a mating pin terminal during insertion into the receptacle terminal. The front wall also serves to provide inwardly stamped extensions or tabs against which the cantilever beam contact arms resiliently abut in order to pre-stress the contact arms thereby increasing the contact force against a mating terminal. The terminal described in this reference also has the advantage of being easily inserted through a seal without damaging the seal. Despite these improvements, it would be desirable to further improve single piece receptacle terminals, particularly in view of reducing material usage and scrap, without compromising robustness and electrical contact properties. It would be further desirable to provide a particularly compact single piece electrical terminal with a well protected contact area. It would be further advantageous to ensure that such terminals can be securely retained in connector housings.